$ php test/compare.php test/Fixtures/lessjs-2.5.3/less/legacy/
... parse /Users/krinkle/Development/less.php/test/Fixtures/lessjs-2.5.3/less/legacy/legacy.less Fail
--- actual
+++ /Users/krinkle/Development/less.php/test/Fixtures/lessjs-2.5.3/css/legacy/legacy.css
@@ -7,7 +7,7 @@
 }
 #units {
   t1: 22em;
-  t2: 22;
+  t2: 22em;
   t3: 2em;
   t4: 22em;
   t5: 22em;

Summary:
* OK: 0
* Fail: 1 (legacy.less)